Rigel 0.0.4 released - Added support for streaming API


#1

rigel is a HMAC-SHA512 implementation optimized for embedded devices. The first version didn’t support streaming messages, but somebody pointed out the importance of this and it’s since been added.

You can find the project on Github and Crates.io.


#2

I think you could make the code a bit more DRY defining module-level types like [u8; 128] and [u8; 64]. I’d like to see more Rust libraries that try to minimize better the heap allocations :slight_smile:


#3

Thanks for taking a look at the code. I’m sorry I don’t really see how that would DRY my code, but I haven’t really used module-level types for these things before. Could you give me an example?


#4

Your code contains:

fn pad_key_to_ipad(key: &[u8]) -> [u8; 128] {

    let mut padded_key = [0x36; 128];
    //...

    padded_key
}

pub fn hmac_sha512(key: &[u8], message: &[u8]) -> [u8; 64] {
    //...
    let mut mac: [u8; 64] = [0u8; 64];
    //...
    mac
}

pub struct HmacSha512 {
    buffer: [u8; 128],
    hasher: Sha512
}

If you define two types like this (their name should be improved):

type Ipad = [u8; 128];
type Mac = [u8; 64];

You can then write:

fn pad_key_to_ipad(key: &[u8]) -> Ipad {

    let mut padded_key = [0x36; 128];
    //...

    padded_key
}

pub fn hmac_sha512(key: &[u8], message: &[u8]) -> Mac {
    //...
    let mut mac: Mac = [0; 64];
    //...
    mac
}

pub struct HmacSha512 {
    buffer: Ipad,
    hasher: Sha512
}

Eventually I hope Rust will allow more DRY code like this:

let mut mac = Mac::default();


#5

That’ll make the meaning behind the numbers a lot clearer too, thanks!